// 进入全屏
export function requestFullScreen() {
    var elem = document.documentElement
    if (elem.requestFullscreen) {
        elem.requestFullscreen()
    } else if (elem.mozRequestFullScreen) {
        elem.mozRequestFullScreen()
    } else if (elem.webkitRequestFullScreen) {
        elem.webkitRequestFullScreen()
    } else if (elem.msRequestFullscreen) {
        // elem.msRequestFullscreen() 没有指定元素
        document.body.msRequestFullscreen()
    }
}
// 退出全屏
export function exitFullscreen() {
    var doc = document
    if (doc.exitFullscreen) {
        doc.exitFullscreen()
    } else if (doc.mozCancelFullScreen) {
        doc.mozCancelFullScreen()
    } else if (doc.webkitCancelFullScreen) {
        doc.webkitCancelFullScreen()
    } else if (doc.msExitFullscreen) {
        document.msExitFullscreen()
    }
}